This project investigates whether ownership structure and related-party transactions are associated with firm performance. With a five-year sample of power companies in China, we find that (1) the positive effect for state ownership suggests that state-owned companies are supported by governments, so that their performance reflects high entry barriers; (2) the negative effect for tradable shares suggests that controlling shareholders might rely on issuing tradable shares for their own private benefits, at the expense of minority shareholders. The evidence suggests that appropriate ownership structure would improve the effectiveness of a firm's corporate governance. We qualitatively investigate related-party transactions in the listed power companies and show their impact on the corporate governance system. Results show that related-party transactions have different impacts on firm performance through transparency and fairness, and if excessive, would have a negative impact. In particular, we use Huaneng International as a case study, pointing out the strengths and weaknesses in its corporate governance system and providing recommendations for changes.